This shared instrumentation proposal is for the acquisition of a new Siemens Symbia T SPECT-CT system. We currently have a number of ongoing research projects that would benefit substantially from a dedicated research scanner that had the capability to perform single photon emission computed tomography (SPECT) as well as allow for anatomical mapping and correlation, and attenuation correction of the functional images. Such a scanner will not only enhance the present studies that measure various aspects of cerebral function, but will allow us to greatly expand the number of types of research projects in this area. Furthermore, the proposed scanner provides substantial improvements in the quality of the CT scanner than previously available. This scanner also has several software programs that aid in the use and integration of the SPECT and CT scans. We currently perform studies measuring cerebral blood flow and several neurotransmitter systems utilizing brain SPECT imaging to study neurological and psychiatric conditions as well as activation states. Studies of neurological and psychiatric conditions include those related to Parkinson's disease and other movement disorders, cocaine addiction, depression, anxiety, and night eating syndrome. Activation studies currently include the study of pain perception and the placebo effect. Our radiochemistry group is continually working on developing new radiopharmaceuticals that will have applications for studying many aspects of cerebral physiology. The most recent include tracers to measure the serotonin transporter and detect pathophysiological changes associated with Alzheimer's disease. The requested scanner is critical for continuing these studies, developing new radiopharmaceuticals, and providing an imaging environment conducive to including many new investigators. The requested scanner also has the ability to perform whole body planar and SPECT imaging which is necessary for biodistribution studies of new radiopharmaceuticals, as well as research studies in cardiology, oncology, and infectious disease. Overall, this scanner will become a major tool for our present and future research programs with a focus on brain SPECT imaging, but also the potential to include many other types of studies. [unreadable] [unreadable]